Multicopter with wide span rotor configuration and protective fuselage

ABSTRACT

An aircraft includes a plurality of rotors and a fuselage. The plurality of rotors are attached to the aircraft at a fixed roll angle and a fixed pitch angle and the plurality of rotors rotate independently of one another. The fuselage includes a side wall with a top edge where the top edge of the side wall is higher than the plurality of rotors.

BACKGROUND OF THE INVENTION

New types of aircraft, such multicopters with wide span rotorconfigurations, are being developed. In one such multicopter, themulticopter has 6 inner rotors (e.g., 3 adjacent to the left (port) sideof the fuselage and 3 adjacent to the right (starboard) side of thefuselage) and 4 outer rotors (e.g., 2 on each side of the multicopter,separated from the fuselage by the inner rotors) for a total of 10rotors. Although such multicopters are useful, further improvementswould be desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the followingdetailed description and the accompanying drawings.

FIG. 1 is a diagram illustrating an embodiment of rotor directions ofrotation in a multicopter.

FIG. 2 is a diagram illustrating an embodiment of the fixed tiltpositions of the rotors in a multicopter.

FIG. 3 is a diagram illustrating a front view and a side view of amulticopter embodiment.

FIG. 4 is a diagram illustrating an embodiment of a float which includesbatteries and a headrest with a cutout.

DETAILED DESCRIPTION

The invention can be implemented in numerous ways, including as aprocess; an apparatus; a system; a composition of matter; a computerprogram product embodied on a computer readable storage medium; and/or aprocessor, such as a processor configured to execute instructions storedon and/or provided by a memory coupled to the processor. In thisspecification, these implementations, or any other form that theinvention may take, may be referred to as techniques. In general, theorder of the steps of disclosed processes may be altered within thescope of the invention. Unless stated otherwise, a component such as aprocessor or a memory described as being configured to perform a taskmay be implemented as a general component that is temporarily configuredto perform the task at a given time or a specific component that ismanufactured to perform the task. As used herein, the term ‘processor’refers to one or more devices, circuits, and/or processing coresconfigured to process data, such as computer program instructions.

A detailed description of one or more embodiments of the invention isprovided below along with accompanying figures that illustrate theprinciples of the invention. The invention is described in connectionwith such embodiments, but the invention is not limited to anyembodiment. The scope of the invention is limited only by the claims andthe invention encompasses numerous alternatives, modifications andequivalents. Numerous specific details are set forth in the followingdescription in order to provide a thorough understanding of theinvention. These details are provided for the purpose of example and theinvention may be practiced according to the claims without some or allof these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

Various embodiments of a multicopter with a wide span rotorconfiguration and protective fuselage are described herein. In someembodiments, the aircraft includes a plurality of rotors (e.g., wherethe plurality of rotors are attached to the aircraft at a fixed rollangle and a fixed pitch angle, and the plurality of rotors rotateindependently of one another) and a fuselage (e.g., which includes aside wall with a top edge, where the top edge of the side wall is higherthan the plurality of rotors). In some figures below, an exemplarymulticopter has 10 total rotors. To maneuver the aircraft, differenttorques are applied to the rotors, which causes the rotors to rotate atdifferent speeds and/or output different thrusts. The height of thefuselage's side walls and/or the position of the rotors relative to thefuselage are designed to protect the pilot. For example, if one of therotors were to break while rotating, the broken rotor parts would becomefast-moving and dangerous projectiles. Since the top of the side wall ishigher than the rotors, any rotor projectiles will hit the side wall ofthe fuselage and not the pilot.

FIG. 1 is a diagram illustrating an embodiment of rotor directions ofrotation in a multicopter. In this example, a multicopter with 10 rotorsis shown with 5 rotors each on the left (port) side and right(starboard) side of the multicopter. Inner rotors 101, 103, 105, 106,108, and 110 are located adjacent to the fuselage (100). Outer rotors102, 104, 107, and 109 are separated from the fuselage (100) by theinner rotors. The arrangement of rotors shown here is sometimes referredto as a wide span rotor configuration. In some embodiments, themulticopter weighs 250 pounds or less. Such a multicopter may qualify asan ultralight aircraft under federal aviation regulation guidelines.

In this example, the inner rotors (101, 103, 105, 106, 108, and 110)overlap with their neighboring or adjacent inner rotor(s). For example,inner rotor 106 overlaps with (and rotates above) inner rotor 108, whichin turn overlaps with (and rotates above) inner rotor 110. Similarly, onthe other side, inner rotor 105 overlaps with (and rotates above) innerrotor 103, which in turn overlaps with (and rotates above) inner rotor101. As will be described in more detail below, to achieve the overlapsshown, the rotors are tilted at various angles and/or are placed atdifferent heights in this example.

In some embodiments, having the inner rotors overlap with each other(one example of which is shown here) is attractive because it permits asmaller, more compact footprint of the multicopter than if the innerrotors did not overlap. A smaller footprint may be desirable because themulticopter takes up less space for transport or when parked, and/or asmaller safety zone is required when taking off or landing. Also, theweight can be reduced with a smaller airframe, which is desirable sinceless power is required to fly the aircraft and/or the range can beextended. The tradeoff with overlapping rotors is that they mayinterfere with each other aerodynamically (e.g., the airflow from onerotor interferes with another rotor) but this impact may be relativelysmall and/or acceptable given the benefits of a smaller footprint. Forexample, the overlap between inner rotors shown here is relatively smalland so the interference may be negligible.

In some embodiments, a multicopter is sized so that it can fit into atrailer or on a flatbed and be towed. For example, because the wingspanis wider than the nose-to-tail length of the multicopter, the exemplarymulticopter may be fit into an enclosed trailer or on an open flatbedtrailer sideways. By having the inner rotors overlap, this makes iteasier to fit the multicopter into standard sized trailers.

Using 10 rotors as shown here may be attractive for a variety ofreasons. For example, 10 rotors maximizes the multicopter's disc areawithin a desired overall size (e.g., the desire to fit the multicopterinto or on a standard-width trailer). Using 10 rotors also helps withredundancy because it permits the multicopter to maintain flight andpossibly allow for some degree of flight precision even if there isrotor failure. It is noted that a rotor failure may require power to becut to a rotor opposite to the failed rotor for symmetry and ease offlight.

In this example, the outer rotors do not overlap with their adjacent orneighboring inner rotors. For example, outer rotor 109 (102) does notoverlap with inner rotor 110 (101) nor with inner rotor 108 (103).Similarly, outer rotor 107 (104) does not overlap with inner rotor 108(103) nor with inner rotor 106 (105). However, the outer rotors dooverlap with each other (e.g., outer rotor 109 (102) overlaps with outerrotor 107 (104)). Having some separation between an outer rotor andadjacent inner rotors (i.e., no overlap) may be desirable because theouter rotors are more susceptible to larger vibrations and/or bouncing.For example, because the outer rotors are located at the distal ends ofthe arms which extend outward from the fuselage, the outer rotors willvibrate or bounce up and down more than the inner rotors will. The innerrotors are also mounted to the floats (e.g., which run from front toback) which further dampens any vibrations or bouncing, whereas theouter rotors are not mounted to the floats. This larger verticaldisplacement of the outer rotors could cause an inner rotor and outerrotor to collide which could damage the rotors. To avoid this, there isno overlap between the outer rotors and the inner rotors in thisconfiguration. Although not shown here, in some embodiments, the twoouter rotors on a given side (e.g., rotor 107 and rotor 109, or rotor102 and rotor 104) do not overlap for this reason (e.g., to avoid apotential collision).

The position or placement of the outer rotors is selected so that theouter rotors are packed fairly efficiently and/or tightly next to thetwo adjacent inner rotors. For example, outer rotor 109 sits in the “V”created by inner rotor 110 and inner rotor 108. This arrangement packsthe rotors in an efficient and/or tight manner which in turn reduces thefootprint of the multicopter.

This diagram also illustrates the directions of rotation of the variousrotors. In this example, rotors 103, 104, 106, 109, and 110 rotate in aclockwise direction when viewed from above. Rotors 101, 102, 105, 107,and 108 rotate in a counterclockwise direction when viewed from above.Or, to put it another way, rotors 101, 102, 105, 106, 109, and 110rotate towards the fuselage and rotors 103, 104, 107, and 108 rotateaway from the fuselage.

It is noted that all of the rotors in a particular column (e.g., goingfrom the front of the multicopter to the rear of the multicopter) havealternating directions of rotation. For example, in the leftmost columnshown, rotor 109 and rotor 107 have alternating directions of rotation.Similarly, in the second column from the left, rotor 110 rotates in aclockwise direction, rotor 108 rotates in a counterclockwise direction,and rotor 106 rotates in a clockwise direction. This alternation of mayenable the multicopter to fly more efficiently. A rotor creates liftwhen the blade is traveling against the direction of wind and does notcreate lift when it spins in the direction of wind. By stacking upalternating rotors one behind the next in the direction of flight (e.g.,typically forwards), the multicopter may experience a consistent amountof lift and/or decrease intervals of decreased lift.

TABLE 1 Directions of rotation for the exemplary rotors shown in FIG. 1.Direction of Rotation Rotor (viewed from above) Right Inner Front Rotor(101) Counterclockwise Right Outer Front Rotor (102) CounterclockwiseRight Inner Middle Rotor (103) Clockwise Right Outer Back Rotor (104)Clockwise Right Inner Back Rotor (105) Counterclockwise Left Inner BackRotor (106) Clockwise Left Outer Back Rotor (107) Counterclockwise LeftInner Middle Rotor (108) Counterclockwise Left Outer Front Rotor (109)Clockwise Left Inner Front Rotor (110) Clockwise

The directions of rotations shown here are selected based on a varietyof factors. In some embodiments, rotors that are opposite to each otheron the aircraft (e.g., where fuselage 100 acts as an axis of symmetry)may rotate in opposing directions to balance torque. For example, rotor101 and rotor 110 are opposite to each other and rotate in oppositedirections to counter the other's torque.

To illustrate the area occupied by the rotors when the rotors are on,the rotors are shown here as a circle and the number of blades is notshown. In some embodiments, a rotor has two blades and the rotors have adiameter of ˜50 inches. A diameter of this size may correspond to thelargest diameter possible for a 10 rotor configuration within theconstraints of the desired multicopter dimensions (e.g., fit into astandard sized trailer).

It may be helpful to describe how the exemplary multicopter can beflown, beginning with how the pilot gets into the multicopter. In somecases, the multicopter will be floating on water and the pilot will getinto the seat in the fuselage by walking on the arms, floats, and/orfuselage of the multicopter as needed. The rotors will be off at thistime, and the pilot will be in no danger from the rotors when gettinginto the multicopter.

Once in the multicopter, the pilot may decide to steer (e.g., whilefloating on the water) the multicopter away from the boarding point tosome takeoff location away from bystanders and/or other multicopters. Insome embodiments, to do this, only the inner middle rotors are turned onand used to maneuver the multicopter to the desired takeoff location.For example, since rotor 103 and rotor 108 are shielded by other rotors,it will be harder for those rotors to hit any bystanders even if theyare on. In some embodiments, only rotors 103 and 108 (i.e., theunexposed rotors) are used to maneuver the multicopter around to protectbystanders. Alternatively, the outer rotors (102, 104, 107, and 109) maybe turned off and only the inner rotors (101, 103, 105, 106, 108, and110) are used in some embodiments to maneuver the aircraft when on thewater. Although this may pose more of a risk, it may be easier and/ormore efficient to maneuver the aircraft using more rotors. In someembodiments, a multicopter has wheels and the multicopter is able tomaneuver on the ground in this manner (e.g., using only shielded rotorsor the inner rotors for safety).

Once the multicopter reaches the desired takeoff location, themulticopter performs a substantially vertical takeoff once a desiredaltitude is reached, the pilot may rotate (e.g., while hovering at thesame altitude) the multicopter about a vertical or yaw axis (not shownhere) so that the multicopter is facing or pointing in some desireddirection (e.g., toward a desired destination). The multicopter thenflies forward, maintaining a constant altitude until the multicopterapproaches a desired landing site (e.g., over water or on land). Thepilot may slow the forward movement of the multicopter, coming to aforward stop generally above the desired landing site while stillhovering and maintaining a constant altitude. The multicopter thendescends vertically. If needed, the pilot may stop the vertical descentand (if desired) move the multicopter laterally left or right (e.g.,while maintaining a constant altitude) in order to avoid objects on theground and/or to better align the multicopter over the desired landingsite. Similarly, during the vertical landing, the pilot may stop thevertical descent and (if desired) rotate the multicopter about verticalor yaw axis so that the multicopter is facing in some desired directionand/or to make it easier to shift left or right in order to land on thedesired landing site.

Each of the rotors is attached in a fixed manner to the exemplarymulticopter with some fixed roll angle and fixed pitch angle. Thefollowing figure shows an example of this.

FIG. 2 is a diagram illustrating an embodiment of the fixed tiltpositions of the rotors in a multicopter. In this example, each rotor'stilt position is described using two angles: a roll angle and a pitchangle. The roll angle is defined by the roll axis (220), sometimesreferred to as an x-axis, where a positive roll angle follows theright-hand direction of rotation (see, for example, the curved arrowabout roll axis 220) and a negative roll angle is in the oppositedirection. Similarly, the pitch angle for each rotor is defined by thepitch axis (222), sometimes referred to as a y-axis, where a positivepitch angle follows the right-hand direction of rotation (see, forexample, the curved arrow about pitch axis 222) and a negative pitchangle is in the opposite direction.

The following table lists the roll angle and pitch angle for each rotorin this example. It is noted that opposite rotors (e.g., where thefuselage acts as an axis of symmetry) have roll angles of the samemagnitude but opposite signs (e.g., rotor 110 has a roll angle of −3°and rotor 101 has a roll angle of 3°) and the same pitch angle (e.g.,both rotor 110 and rotor 101 have pitch angles of 0°). Generallyspeaking, the roll angles and pitch angles have magnitudes within therange of 0 degrees and 10 degrees.

TABLE 2 Tilt positions for the exemplary rotors shown in FIG. 2. RollAngle Pitch Angle Rotor (in degrees) (in degrees) Right Inner FrontRotor (201) 3.0 0.0 Right Outer Front Rotor (202) −2.0 −3.0 Right InnerMiddle Rotor (203) −4.0 −9.0 Right Outer Back Rotor (204) −2.0 −10.0Right Inner Back Rotor (205) −7.0 −2.0 Left Inner Back Rotor (206) 7.0−2.0 Left Outer Back Rotor (207) 2.0 −10.0 Left Inner Middle Rotor (208)4.0 −9.0 Left Outer Front Rotor (209) 2.0 −3.0 Left Inner Front Rotor(210) −3.0 0.0

For convenience, an arrow is shown over each rotor which gives a generalor rough sense of each rotor's tilt position For example, if each rotoris conceptually thought of as a plane, a hypothetical ball placed onthat plane would roll (e.g., generally or roughly) in the direction ofthe arrow shown. In general, all of the rotors are tilted slightlyforward, with the inner middle rotors (203 and 208) more so.

There are a number of benefits associated with the tilt positions shownin this example. First, all of the rotors have a slight (e.g., ˜5degrees) forward bias so that when the aircraft is flying forwards, thebody of the aircraft remains level. Also, the tilt positions of therotors angles are selected to maximize the aircraft's ability to yawwhile minimizing the impact of losing any single rotor. The more a rotoris tilted, the more it contributes to yawing the vehicle when it is spedup or down.

The rotors are mounted to the multicopter (e.g., more specifically, tothe floats for the inner rotors and to the arms for the outer rotors) ina fixed manner at the roll angles and pitch angles shown in a fixedmanner. In other words, the rotors cannot change their tilt positionsfrom the positions shown. To maneuver, each rotor is independentlycontrollable (e.g., different amounts of torque can be applied to eachrotor), such that each rotor can rotate at a different speed or output adifferent amount of thrust.

The various tilt positions shown here enable the multicopter to maneuvermore efficiently compared to some other multicopter designs. Forexample, consider another multicopter where the rotors only tilt forwardor backward to some degree (i.e., all of the rotors have a roll angle of0°). To move sideways (e.g., left or right), such a multicopter may haveto expend more power because none of the rotors have a non-zero rollangle which would help to move the multicopter laterally to the left orright. In contrast, the multicopter shown here can move sideways in amore efficient manner because the rotors have non-zero roll angles. Forexample, to move laterally to the right, more torque would be applied torotors 206-209, which would create a thrust differential and move themulticopter to the right. Since rotors 206-209 have positive roll angles(e.g., the tops of those rotors are tilted inward toward the fuselage),some of their overall thrust becomes lateral thrust and some becomesvertical thrust. That is, the positive roll angles of rotors 206-209more efficiently generate lateral thrust and movement to the rightcompared to rotors with roll angles of 0.

The following figure shows front and side views of the exemplarymulticopter and discusses some landing and safety features.

FIG. 3 is a diagram illustrating a front view and a side view of amulticopter embodiment. In the example shown, diagram 300 shows a frontview of the exemplary multicopter. This multicopter is capable of takingoff and landing on a variety of surfaces, including water and land (notshown here). Waterline 302 shows an example of how high the water isexpected to come up to on the multicopter when the multicopter isfloating on the surface of the water (e.g., with the rotors off).

From the front view shown in diagram 300, floats (304) are visible. Thefloats serve a number of functions or purposes. One function they serveis to displace water which generates buoyancy and enables themulticopter to float (e.g., when the rotors are off and are notproviding lift). The inner rotors (306) are mounted to the top of thefloats (304). Structurally, this helps to stabilize the inner rotors(e.g., since the float is more substantial than the arms to which theouter rotors (312) are attached) and reduces vibrations and/or bouncingexperienced by the inner rotors. As will be described in more detailbelow, the floats are also used to store the batteries which power therotors.

The dimensions of the float in this example are dictated and/or set inorder to satisfy various design goals and/or objectives. As diagram 300shows, from the front view, the floats look like air foils where thefloats (e.g., observed from the front) are relatively narrow. Thisreduces drag when the multicopter is flying forwards. Also, because theinner rotors are mounted to the floats, there is a significant amount ofdowndraft from the inner rotors on the floats, so the floats also act asairfoils when viewed from above. The relatively thin width of the floatsminimizes the downward force on the multicopter from the inner rotors'downdraft.

The length (e.g., from front to back) of the floats is dictated by thediameter of the 3 inner rotors and the amount of overlap between theinner rotors in this example. That is, the length of the float isroughly the shortest length which can fit the 3 inner rotors with thedesired amount of overlap and not substantially more than that.

Since the floats also have to displace enough water to providesufficient buoyancy for the multicopter to float, the remainingdimension (in this case, the height of the floats) is selected to enablethat. To put it another way, since drag and downdraft considerationssubstantially limit the width of the floats and the length of the floatsis substantially dictated by the diameter and packing of the innerrotors, that only leaves the height of the rotors which can be adjustedor otherwise set to provide sufficient buoyancy. It is noted that inthis example, part of the fuselage is submerged when the aircraft isfloating so that the floats do not need to provide all of the necessarybuoyancy for the aircraft to float; this is accounted for in theselection of the float height.

In some embodiments, the floats are filled with air (e.g., in additionto any batteries or other components which are located in the floats) tohelp with buoyancy. In some embodiments, the floats have bottoms made ofa thick and/or robust material so that the multicopter can be land onrough terrain or surfaces other than water. In some embodiments, thebottoms of the floats are curved. This may be desirable for waterlandings because it increases stability during water landings.

The front view shown in diagram 300 also illustrates a number of safetyfeatures associated with the fuselage. First, with respect to the pilot,the top edge of the fuselage's side wall (308) is at substantially thesame height as the pilot's shoulder (310) when the pilot is seated. Thehigh side walls (e.g., relative to the pilot's seated position) helps toprotect the pilot's arms when the rotors of the multicopter are rotatingand the pilot is seated. To touch the spinning inner rotors, the pilot'sarms would have to go over the side wall, and even very long limbedpeople will not be able to touch the inner rotors while seated due tothe tall side walls. In contrast, if the side walls were lower (e.g., atwaist or stomach height), it would be easier for a pilot to reach overand touch a spinning inner rotor.

Another safety feature of the fuselage relates to the position and/orshape of the fuselage, relative to the rotors. If a rotor were to breakinto pieces while rotating (e.g., turning the rotor pieces intoprojectiles), the projectiles can actually project at a non-zero angle,causing the debris to leave the plane of rotation. In this example, theside wall's height is selected to accommodate for this, for examplebased on testing to determine a range of angles (e.g., from the plane ofrotation) any projectiles are likely to be projected at if a rotor weredamaged. For example, based on testing and/or simulation, heavier andfaster moving particles do not tend to go more than ±5 degrees from theplan of rotation when they break apart. This means that the exposed partof the pilot (e.g., above the top edge of the side walls) should not benear the rotors' plane(s) of rotation plus some angle of projection. Forthis reason, a tall side wall is again useful.

The fuselage is also elevated relative to the rotors to further separatethe top edge of the side wall (308) from the plane(s) in which therotors rotate. With the multicopter configuration shown here, a rotorprojectile would hit the fuselage near the midsection of the fuselage(314), not near the top edge of the side wall (308) where the pilot isexposed. In some embodiments, the midsection of the fuselage (e.g.,where a projectile from a broken rotor might hit) is reinforced orotherwise designed to protect the pilot should a blade or rotor strikethe fuselage.

Returning briefly to the tilt positions shown in Table 2, at least someof the rotors are also tilted in a way that reduces the likelihood of apilot getting struck by a broken rotor. Note that almost all of therotors (e.g., except for rotors 201 and 210) have roll angle signs(e.g., positive or negative) which mean that the rotors are mounted suchthat the top of each rotor tilts inward toward the fuselage. Returningto diagram 300 in FIG. 3, this means a rotor projectile rotor would godownward (e.g., away from the pilot) as opposed to upward (e.g., towardthe pilot). Thus, the tilt positions of at least some of the rotors alsohelp to protect the pilot.

Returning to diagram 320 in FIG. 3, the elevated position of thefuselage (e.g., where the bottom of the fuselage is connected to thearms (316) of the multicopter) may also be desirable because of theseparation between the bottom of the fuselage and the ground. Thisseparation between the fuselage and the ground permits the multicopterto land on uneven and/or rocky ground where a rock or protrusion mightotherwise damage a lower-hanging fuselage.

At the midsection (314), the fuselage narrows inward (e.g., the sidewall includes a top panel which runs vertically, a middle panel whichruns (e.g., inwards) horizontally, and a bottom panel which runsvertically) so that the bottom portion of the fuselage is narrower thanthe top portion of the fuselage. The wider top enables the pilot to moreeasily enter and exit the multicopter and more comfortably sit in themulticopter. For example, although not shown here, the inside of thefuselage may have arm rests. These arm rests may be located above and/orformed by the narrowing of the fuselage at the midsection (314).

The narrower bottom of the fuselage permits the inner rotors to becloser to the center of the multicopter, which reduces the span (width)of the multicopter. Note, for example, that the narrowing of thefuselage at the midsection (314) creates an overhang beneath which thetips of the inner rotors (306) spin. This permits the rotors to besqueezed in more tightly and for the span (width) of the multicopter tobe smaller than if the fuselage were the same width from top to bottom.The narrowing shape also has weight advantages.

Although not shown here, in some embodiments, the seat of a multicopterincludes a seatbelt for strapping in a pilot (e.g., in a recumbentand/or seated position). When the rotors are spinning, the seatbelt mayhelp to prevent the pilot from touching the spinning rotors. Also,during a crash or rollover, a seatbelt may keep the pilot safer.

Diagram 320 shows a side view of the multicopter. As shown here, the topof the headrest (322) is higher than the top of the pilot's head (324)when the pilot is seated. The headrest is protective and reinforced sothat if the multicopter flips and/or rolls, the headrest protects thepilot's head from being crushed. In some embodiments, the headrest isreinforced by being part of a roll cage or other protective frame whichextends throughout the fuselage to prevent the fuselage from collapsinginward and crushing additional body parts, such as the pilot's arms,torso, and legs.

The side view shown in diagram 320 also illustrates the different rotorheights (which generally speaking are within the range of 45 cm-55 cmoff the ground) which help to achieve (e.g., in combination with thevarious tilt positions of the rotors) the rotor overlaps shown in FIG. 1and FIG. 2.

TABLE 3 Relative heights of the exemplary rotors shown in FIG 3. RotorHeight Inner Front Rotor (326) 48 cm Outer Front Rotor (328) 52 cm InnerMiddle Rotor (330) 48 cm Outer Back Rotor (332) 53 cm Inner Back Rotor(334) 50 cm

To address height differences in pilots, a variety of techniques may beused. In some embodiments, the seat is adjustable so that is can beraised or lowered depending upon the pilot's height. For example, ashorter pilot may not be able to see over the side wall or front walland an adjustable seat would be raised. Conversely, an adjustable seatmay be lowered for a taller pilot so that a taller pilot's head remainsbelow the top of the headrest and/or their shoulder is substantially thesame height as the top edge of the side wall. Other techniques,including booster seats for shorter pilots or swappable/removable seats,may also be employed.

The multicopter shown here is merely exemplary and is not intended to belimiting. For example, this multicopter does not have a windshield butother embodiments may include a windshield for comfort and/orprotection. In some embodiments, the windshield is also used as a headsup display. In some embodiments, the cockpit is enclosed so that thepilot is protected from all sides or angles.

FIG. 4 is a diagram illustrating an embodiment of a float which includesbatteries and a headrest with a cutout. For clarity, the blades of therotors on this side of multicopter are not shown. In this example, thefloat (400) includes 5 batteries (402), one for each rotor on this sideof the multicopter. By having an independent battery for each rotor,multiple rotors will not fail if a single battery goes out.

Storing the batteries in the float may be desirable for safety reasons.In the event of a hard landing (assuming the aircraft does not flipover), the batteries will strike the ground before the pilot will,absorbing much of the kinetic energy of the impact and reducing impactforce on the pilot. Similarly, in the event of a rollover, the batteriesin the floats help to absorb energy to protect the pilot. For example,as the batteries decelerate, some of the structure in the floats isbroken and/or sacrificed in order to protect the pilot.

In some embodiments, the float (400) is carbon based (e.g., carbonfiber), which is relatively lightweight and permits a desired shape tobe achieved. For example, if the floats were instead made of aninflatable material, it would be more difficult to achieve the desired(e.g., air foil) shape described above. Carbon related materialstherefore can achieve the desired shape, while having sufficient oradequate thermal conductivity to dissipate the heat from the batteries(e.g., because the floats must have a variety of properties, includingthe ability to dissipate heat from the batteries so that the batteriesdo not overheat). In some embodiments, to help with thermalconductivity, the walls of the float are kept relatively thin (e.g.,thick enough to achieve some desired structural performance, but thinenough to sufficiently dissipate heat).

Placing the batteries in the float also keeps the pilot safe in theevent the batteries fail and/or overheat. Some other aircraftconfigurations may place the batteries under the pilot's seat, which isdangerous because a battery failure can include the battery catching onfire, emitting noxious fumes, and/or exploding. Even a battery whichbecomes hot but does not fail could be uncomfortable for the pilot.

To access the batteries and other components inside the float, the floathas two access panels (406) on the top surface of the float. Duringnormal operation when access to the interior of the floats is notneeded, the access panels are closed to protect the batteries and othercomponents inside the float from water, dirt, debris, etc. When accessto the interior of the float is desired, the access panel(s) may beopened. In various embodiments, the access panels may have a variety ofconfigurations or tops, such as a completely removable lid, a hingedlid, a sliding cover, etc. In various embodiments, the access panels areheld in place using an adhesive, screws, locks, etc. For simplicity andreadability, only two access panels are shown here. An actual prototypeof the aircraft includes four access panels per float.

The headrest (410) in this example contains a cutout. For context, thepilot's head when seated is shown with a dotted circle (412) and asshown the cutout is located above the expected position of the pilot'shead. The cutout in the headrest reduces the drag when the multicopteris flying forward because it permits airflow through the cutout whilestill protecting the pilot should the multicopter flip over. Incontrast, air cannot pass through a solid headrest (see, e.g., FIG. 3)when the multicopter is flying forward which will result in higher dragor wind resistance.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, the invention is not limitedto the details provided. There are many alternative ways of implementingthe invention. The disclosed embodiments are illustrative and notrestrictive.

What is claimed is:
 1. An aircraft, comprising: a plurality of rotors,wherein: the plurality of rotors are attached to the aircraft at a fixedroll angle and a fixed pitch angle; the plurality of rotors rotateindependently of one another; and the plurality of rotors include: anouter back rotor which is attached to the aircraft at a highest heightassociated with the plurality of rotors; an outer front rotor which isattached to the aircraft at a second highest height associated with theplurality of rotors; an inner back rotor which is attached to theaircraft at a third highest height associated with the plurality ofrotors; an inner front rotor which is attached to the aircraft at alowest height associated with the plurality of rotors; and an innermiddle rotor which is attached to the aircraft at the lowest heightassociated with the plurality of rotors; and a fuselage which includes aside wall with a top edge, wherein the top edge of the side wall ishigher than the plurality of rotors.
 2. The aircraft recited in claim 1,wherein the plurality of rotors further include: a right inner frontrotor which is configured to rotate in a first direction; a right outerfront rotor which is configured to rotate in the first direction; aright inner middle rotor which is configured to rotate in a seconddirection; a right outer back rotor which is configured to rotate in thesecond direction; a right inner back rotor which is configured to rotatein the first direction; a left inner back rotor which is configured torotate in the second direction; a left outer back rotor which isconfigured to rotate in the first direction; a left inner middle rotorwhich is configured to rotate in the first direction; a left outer frontrotor which is configured to rotate in the second direction; and a leftinner front rotor which is configured to rotate in the second direction.3. The aircraft recited in claim 1, wherein the plurality of rotorsfurther include: a right inner front rotor which is configured to rotatein a counterclockwise direction when viewed from above; a right outerfront rotor which is configured to rotate in the counterclockwisedirection when viewed from above; a right inner middle rotor which isconfigured to rotate in a clockwise direction when viewed from above; aright outer back rotor which is configured to rotate in the clockwisedirection when viewed from above; a right inner back rotor which isconfigured to rotate in the counterclockwise direction when viewed fromabove; a left inner back rotor which is configured to rotate in theclockwise direction when viewed from above; a left outer back rotorwhich is configured to rotate in the counterclockwise direction whenviewed from above; a left inner middle rotor which is configured torotate in the counterclockwise direction when viewed from above; a leftouter front rotor which is configured to rotate in the clockwisedirection when viewed from above; and a left inner front rotor which isconfigured to rotate in the clockwise direction when viewed from above.4. The aircraft recited in claim 1, wherein the plurality of rotorsfurther include: a right inner front rotor which is attached to theaircraft at a positive roll angle and a zero pitch angle; and a leftinner front rotor which is attached to the aircraft at a negative rollangle and a zero pitch angle.
 5. The aircraft recited in claim 1,wherein the plurality of rotors further include: a right outer frontrotor which is attached to the aircraft at a negative roll angle and anegative pitch angle; a right inner middle rotor which is attached tothe aircraft at a negative roll angle and a negative pitch angle; aright outer back rotor which is attached to the aircraft at a negativeroll angle and a negative pitch angle; a right inner back rotor which isattached to the aircraft at a negative roll angle and a negative pitchangle; a left inner back rotor which is attached to the aircraft at apositive roll angle and a negative pitch angle; a left outer back rotorwhich is attached to the aircraft at a positive roll angle and anegative pitch angle; a left inner middle rotor which is attached to theaircraft at a positive roll angle and a negative pitch angle; and a leftouter front rotor which is attached to the aircraft at a positive rollangle and a negative pitch angle.
 6. The aircraft recited in claim 1,wherein: the plurality of rotors further include: a right outer frontrotor which is attached to the aircraft at a negative roll angle and anegative pitch angle; a right inner middle rotor which is attached tothe aircraft at a negative roll angle and a negative pitch angle; aright outer back rotor which is attached to the aircraft at a negativeroll angle and a negative pitch angle; a right inner back rotor which isattached to the aircraft at a negative roll angle and a negative pitchangle; a left inner back rotor which is attached to the aircraft at apositive roll angle and a negative pitch angle; a left outer back rotorwhich is attached to the aircraft at a positive roll angle and anegative pitch angle; a left inner middle rotor which is attached to theaircraft at a positive roll angle and a negative pitch angle; and a leftouter front rotor which is attached to the aircraft at a positive rollangle and a negative pitch angle; and the plurality of rotors areattached to the aircraft at roll angles and pitch angles with magnitudesin the range of 0 degrees and 10 degrees.
 7. The aircraft recited inclaim 1, wherein the fuselage narrows at the midsection of the fuselage.8. The aircraft recited in claim 1, wherein the fuselage narrows at themidsection of the fuselage creating an overhang beneath which at leastpart of an inner middle rotor rotates.
 9. The aircraft recited in claim1, wherein: the plurality of rotors are attached to the aircraft atheights in the range of 45 cm-55 cm.
 10. The aircraft recited in claim1, wherein the fuselage further includes a headrest with a cutout. 11.An aircraft, comprising: a plurality of rotors, wherein: the pluralityof rotors are attached to the aircraft at a fixed roll angle and a fixedpitch angle; and the plurality of rotors rotate independently of oneanother; a fuselage which includes a side wall with a top edge, whereinthe top edge of the side wall is higher than the plurality of rotors;and a left float and a right float, wherein: a left inner front rotor, aleft inner middle rotor, and a left inner back rotor are attached to theleft float; a right inner front rotor, a right inner middle rotor, and aright inner back rotor are attached to the right float; the left floatincludes a first plurality of batteries for the left inner front rotor,the left inner middle rotor, the left inner back rotor, a left out frontrotor, and a left outer back rotor; and the right float includes asecond plurality of batteries for the right inner front rotor, the rightinner middle rotor, the right inner back rotor, a right out front rotor,and a right outer back rotor.
 12. The aircraft recited in claim 11,wherein: the left float includes at least one access panel on a topsurface of the left float; and the right float includes at least oneaccess panel on a top surface of the right float.
 13. The aircraftrecited in claim 11, wherein the plurality of rotors include: the rightinner front rotor which is configured to rotate in a first direction;the right outer front rotor which is configured to rotate in the firstdirection; the right inner middle rotor which is configured to rotate ina second direction; the right outer back rotor which is configured torotate in the second direction; the right inner back rotor which isconfigured to rotate in the first direction; the left inner back rotorwhich is configured to rotate in the second direction; the left outerback rotor which is configured to rotate in the first direction; theleft inner middle rotor which is configured to rotate in the firstdirection; the left outer front rotor which is configured to rotate inthe second direction; and the left inner front rotor which is configuredto rotate in the second direction.
 14. The aircraft recited in claim 11,wherein the plurality of rotors include: the right inner front rotorwhich is configured to rotate in a counterclockwise direction whenviewed from above; the right outer front rotor which is configured torotate in the counterclockwise direction when viewed from above; theright inner middle rotor which is configured to rotate in a clockwisedirection when viewed from above; the right outer back rotor which isconfigured to rotate in the clockwise direction when viewed from above;the right inner back rotor which is configured to rotate in thecounterclockwise direction when viewed from above; the left inner backrotor which is configured to rotate in the clockwise direction whenviewed from above; the left outer back rotor which is configured torotate in the counterclockwise direction when viewed from above; theleft inner middle rotor which is configured to rotate in thecounterclockwise direction when viewed from above; the left outer frontrotor which is configured to rotate in the clockwise direction whenviewed from above; and the left inner front rotor which is configured torotate in the clockwise direction when viewed from above.
 15. Theaircraft recited in claim 11, wherein the plurality of rotors include:the right inner front rotor which is attached to the aircraft at apositive roll angle and a zero pitch angle; and the left inner frontrotor which is attached to the aircraft at a negative roll angle and azero pitch angle.
 16. The aircraft recited in claim 11, wherein theplurality of rotors include: the right outer front rotor which isattached to the aircraft at a negative roll angle and a negative pitchangle; the right inner middle rotor which is attached to the aircraft ata negative roll angle and a negative pitch angle; the right outer backrotor which is attached to the aircraft at a negative roll angle and anegative pitch angle; the right inner back rotor which is attached tothe aircraft at a negative roll angle and a negative pitch angle; theleft inner back rotor which is attached to the aircraft at a positiveroll angle and a negative pitch angle; the left outer back rotor whichis attached to the aircraft at a positive roll angle and a negativepitch angle; the left inner middle rotor which is attached to theaircraft at a positive roll angle and a negative pitch angle; and theleft outer front rotor which is attached to the aircraft at a positiveroll angle and a negative pitch angle.
 17. The aircraft recited in claim11, wherein: the plurality of rotors include: the right outer frontrotor which is attached to the aircraft at a negative roll angle and anegative pitch angle; the right inner middle rotor which is attached tothe aircraft at a negative roll angle and a negative pitch angle; theright outer back rotor which is attached to the aircraft at a negativeroll angle and a negative pitch angle; the right inner back rotor whichis attached to the aircraft at a negative roll angle and a negativepitch angle; the left inner back rotor which is attached to the aircraftat a positive roll angle and a negative pitch angle; the left outer backrotor which is attached to the aircraft at a positive roll angle and anegative pitch angle; the left inner middle rotor which is attached tothe aircraft at a positive roll angle and a negative pitch angle; andthe left outer front rotor which is attached to the aircraft at apositive roll angle and a negative pitch angle; and the plurality ofrotors are attached to the aircraft at roll angles and pitch angles withmagnitudes in the range of 0 degrees and 10 degrees.
 18. The aircraftrecited in claim 11, wherein the fuselage narrows at the midsection ofthe fuselage.
 19. The aircraft recited in claim 11, wherein the fuselagenarrows at the midsection of the fuselage creating an overhang beneathwhich at least part of an inner middle rotor rotates.
 20. The aircraftrecited in claim 11, wherein the plurality of rotors are attached to theaircraft at heights in the range of 45 cm-55 cm.
 21. The aircraftrecited in claim 11, wherein the fuselage further includes a headrestwith a cutout.